Webber fastest in the rain

On the day Webber also pledged his future to Red Bull for next year by signing a 12-month contract extension, the 35-year-old appears determined to add icing to the cake by grabbing pole in qualifying.

Webber again finished out in front, albeit with a lap nearly 19 seconds slower than his leading time from Friday when the drivers managed some dry running in between the showers.

The rain started falling just a few minutes before the start of the final hour-long run and grew in intensity in the early stages.

As the drivers ventured out onto the circuit to conduct a customary installation lap, McLaren's Jenson Button reported over the in-car radio that if they had been racing it would have been red flagged. The 31-year-old further added the conditions on track were "worse than we had in Canada" when that particular race in June included a two-hour delay due to torrential rain.

Midway through the session in Spa, however, the rain lifted, at least allowing the field some running for 30 minutes, even if it was predominantly on the full-wet tyres.

Webber posted a time of two minutes 8.988 seconds, a fraction ahead of Lewis Hamilton in his McLaren who came close to deposing Webber in the dying stages.

The Briton, however, missed out by just 0.058secs, with the leading duo comfortably clear of Toro Rosso's Jaime Alguersuari as the Spaniard was almost a second adrift.

Button finished 1.2secs down in fourth, and along with Webber and Ferrari's Felipe Massa completed the least amount of laps of just seven, with reigning champion Sebastian Vettel fifth quickest.

Overall, 14 seconds separated Webber from Massa who was down in 23rd, with only Ferrari team-mate Fernando Alonso not setting a time and so propping up the timesheet.